One of the things I noticed after upgrading to macOS 26 was that I would sometimes fail when trying to resize windows – I’d try to grab the corner, but nothing would happen.
It turns out that this isn’t clumsiness on my part, but rather a design error by Apple – and that’s because the corners of windows aren’t really rounded …
Those who’ve been using Macs for a long time may recall that windows used to have a visual indicator in the bottom right-hand corner showing that they could be resized and providing a grab handle. John Gruber noted that John Siracusa highlighted this in his review of Mac OS X Lion way back in 2011.
It clearly doesn’t make sense to have that handle anymore since we can, of course, grab any corner to resize a window. But the much larger corner radiuses in macOS 26 created a problem, as developer Norbert Heger points out.
Since upgrading to macOS Tahoe, I’ve noticed that quite often my attempts to resize a window are failing. This never happened to me before in almost 40 years of using computers. So why all of a sudden? It turns out that my initial click in the window corner instinctively happens in an area where the window doesn’t respond to it. The window expects this click to happen in an area of 19 × 19 pixels, located near the window corner. If the window had no rounded corners at all, 62% of that area would lie inside the window. But due to the huge corner radius in Tahoe, most of it – about 75% – now lies outside the window.
He illustrates this with green shading showing where most of us would instinctively click to grab the corner of a window and contrasts this with red shading showing the actual active area.
That’s the reason that this everyday action so often now fails: visually, the corners are rounded, but they are actually coded as square.
Additionally, John Gruber points out the visual mess created by this anomaly between the visual and logical versions of window corners. The scrollbars think they are sitting inside a rectangle with square corners.
It seems controversy around macOS 26 Tahoe design isn’t going away anytime soon.
Photo by Declan Sun on Unsplash